SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '029e301c1da9806febd1a964c3f19771146c7338ae1185753266cd9377a92e18' 
  AND token = 'pdMhlNzK8KddkiNEnOM291Z9vlyHOcG+oFDfJAK3VwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}